Multiple couple printing press with controls for sequential and simultaneous cylinder interruption



Oct. 21, 1969 J, VANDEMAN ETAL 3,473,468

MULTIPLE COUPLE PRINTING PRESS WITH CONTROLS FOR SEQUENTIAL AND SIMULTANEOUS CYLINDER INTERRUPTION Filed March 23, 1966 2 Sheets-Sheet INVENTORS JACK E. VA/VDfMA/V HOWARD J L Mi ATT' RNEYS Oct. 21, 1969 J, VANDEMAN ETAL 3,473,468

MULTIPLE COUPLE PRINTING PRESS WITH CONTROLS FOR SEQUENTIAL AND SIMULTANEOUS CYLINDER INTERRUPTION Filed March 23, 1966 2 Sheets-Sheet TRIP CON TROLL El? I i l lia-(h V @825 --/NYENT0R JACK E. VANDEMAN V H W 1 4 HOWARD J. SEEL 9W b-733 M Br 22-2 ,4 7' ORNEYS US. Cl. 101-437 7 Claims ABSTRACT OF THE DISCLQSURE Printing press controlled by repetitive timing signals which effect operation of electromechanical mechanisms to throw the printing units of a printing press between printing and non-printing conditions as the first sheet and last sheet respectively of a stream of sheets proceeds through the press. Each printing unit has a plurality of elements which are to be thrown between printing and nonprinting conditions in sequence under the control of the timing signals. The printing press has additional control means for effecting operation of the electrical controls for each printing unit to actuate the controls within 360 of press revolution to throw all the units to a printing condition in response to the timing signals except for the printing pressure and to throw all the elements of a nonprinting condition after a predetermined number of press revolutions. Circuitry is also provided for throwing the plate to the blanket cylinder independently of effecting the other operations for each printing unit.

The present invention relates to a printing press and more particularly to the manner of controlling the operation of the printing press.

An important object of the present invention is to provide a multi-unit lithographic printing press or the like in which the inkers are thrown off when the printing pressure is thrown off and in which the blanket cylinders can be inked for a predetermined, preferably a pre-selectable, number of press revolutions without throwing on the impression cylinders.

Another object of the present invention is to provide a new and improved multi-unit printing press in which inkers, plate and blanket pressure and impression and blanket pressure of each unit are thrown on and off in sequence within 360 of press rotation with the throwing on and off of the printing units after the first unit being delayed un til the preceding unit has tripped on or off to trip the unit in sequence as a sheet moves through the press and in which control means may be set to cause the units to trip on, except for the printing pressure, without delay and to then trip ofi" after a predetermined number of press revolutions.

Another object of the present invention is to provide a new and improved printing press as in the preceding object wherein the control means includes a revolution counter which may be set to select a predetermined number of press revolutions that the units are to remain on in response to the control means.

A further object of the present invention is to provide a new and improved multi-unit printing press in which electrical controls are provided in each unit for throwing the inkers on and off, the plate on and off, and the impression on and off with the controls being operable to throw the printing units on in sequence or to throw on selected movements without delay.

Yet another object of the present invention is to provide a new and improved printing press in which pulse signals are derived during the revolution of the press and are used to initiate the throwing on of the respective printnite States Patent "ice ing units in their proper sequence in combination with signals from the control means for the preceding units which indicate that the control means has been set to throw on the preceding units.

Further objects and advantages of the present invention will be apparent from the following detailed description of the preferred embodiment made with reference to the accompanying drawings forming a part of the present specification for all matter disclosed therein and in which:

FIG. 1 is a showing of a printing press with which the press invention may be used;

FIG. 2 is a showing of a throw mechanism for the press of FIG. 1;

FIG. 3 is a schematic circuit diagram of a control circuit for controlling the throw mechanisms of the press; and

FIG. 4 is a circuit diagram of a modified control circuit.

Referring to the drawings, FIG. 1 illustrates a multiunit lithographic printing press having a plurality of units with each unit comprising an impresson cylinder 12, a blanket cylinder 13, a plate cylinder 14 and an inking and dampening mechanism 15 including ink form rolls 16 and dampening form rolls 17 for applying ink and dampening fluid to the plate cylinder. Transfer cylinders T transfer the sheets between units with the path of sheet travel being such that it takes more than one but less than two revolutions of the press for the sheet to travel between units.

Conventionally, each printing unit of a press is provided with movements for throwing the inking mechanisms on and otf the plate cylinder (ink on and off), for throwing the plate and blanket cylinders on and off pressure (plate on and off), and for throwing the blanket and impression cylinders on and 0E pressure (impression on and off). The movements in each unit occur in a predetermined sequence to render a unit inoperative to print a sheet and to throw the unit from a printing to a non-printing condition. Conventionally, the actual movements are cam operated and the cams determine the time during a press revolution that the respective movements are actuated.

In a multi-unit printing press, the printing units are thrown on in sequence as the first sheet moves through the press so that the printing units are not thrown on until the sheet arrives at the printing unit. Similarly, the printing units are conventionally thrown off in sequence so that as the last sheet to be printed leaves the first unit, the first unit will be thrown off but the other units will remain on so that the sheet will be printed as it proceeds through the press with each unit being thrown on after it prints the sheet.

In accordance with the present invention, the mechanism for each unit for throwing on and off the inker, plate and impression are electrically controlled with the controls being such that respective mechanisms of the printing units can be operated to throw the press on in sequence or can be operated without delay to allow the preceding units to operate first, the sequential operation of the press preferably being controlled by a sequencing circuit which renders each unit effective to print in response to a pulse from a pulse generator and a signal from the preceding unit so that the throwing on of each unit after the first is delayed until the sheet reaches the unit. The controls are also such that all of the printing units can be thrown on, with the exception of the impression cylinders, without delay so that the printing cylinder may have ink applied thereto for one or more revolutions of the cylinder and the units then automatically thrown off.

In the illustrated press, the on and off movements of the cylinders and the inkers are cam actuated and the on movement occurs if a solenoid is de-energized during a control period in the press cycle and an off movement occurs if the solenoid is energized ,during the cycle or during the control period in the cycle. Such a throw mechanism is shown and described in Harrold et al. Patent No. 2,578,700 and in Albrecht Patent No. 2,615,- 393. Essentially, the trip mechanisms may comprise an operating member 20 which is operated in one direction to throw the cylinder or inker mechanism on and in the opposite direction to throw it off.

In the case of cylinders, the operating member may operate a conventional eccentric for supporting the cylinder and in the case of an inker the mechanism may operate a cam throw off plate for lifting the form rollers. The operating member 20 is pivotally connected at one end to a crank arm fixed to a shaft 21 and is moved in its throw on and throw off movements by oscillating the shaft. The shaft 21 is rotated to effect either the throw on or the throw off movement by a throw member 22 which is reciprocated in work and return strokes by a cam 23. The throw member 22 has a shoulder 24 for engaging a roller 26 carried by a member 27 fixed to the shaft 21 as the throw member is moved through its work stroke to move the roller 26 in a clockwise direction. The member 22 also has a shoulder 28 which is adapted to engage a roller 30 carried by the member 27 on the opposite side of the shaft from the roller 26 to rotate the shaft 21 in a counterclockwise direction when engaged by the shoulder 28 as the operating member 22 is moved through its work stroke. The throw member 22 has one position in which the shoulder 24 is adapted to engage the roller 26 and a second position in which the shoulder 28 is adapted to engage the roller 30 when the operating member 22 is reciprocated through its work stroke by the cam 23. The operating member 22 is reciprocated from the cam 23 by a cam follower 32 which cooperates with the cam 23 and which is carried by one end of a pivoted arm 33, the latter being biased into engagement with the cam 23. The throw member 22 is pivoted to the arm 33 intermediate the ends thereof and as the cam 23 reciprocates the cam follower 32, the throw member 22 is reciprocated through return and work strokes.

The position of the throw member 22 may be controlled by various mechanisms and latches of the types illustrated in the aforesaid patents. For the sake of simplicity and clarity, the operating member 22 is shown as biased to a position for throwing on the mechanism by a spring 35 and as being moved against the bias of the spring 35 by the operation of a solenoid 36. However, it will be understood that the solenoid 36 may operate, as in the aforesaid patents, through latches and cams to prevent the operating member 22 from being in the throw on position at the time that the cam 23 is moved through its work stroke.

In the preferred and illustrated embodiment of the present invention, separately controllable trip mechanisms are provided for throwing the plate on relative to the blanket, the inker on relative to the plate cylinder, and the impression on relative to the blanket cylinder and a respective control solenoid is provided for each throw movement.

Control means for tripping the printing press units on and off in sequence by energizing and de-energizingtrip solenoids are known and have been described in the patented art, see Albrecht Patent No. 2,615,393. Conventionally, such a control means may comprise circuit means for de-energizing the trip solenoids of each unit to maintain the unit in an off condition until the preceding unit has been thrown on. FIG. 3 is a schematic diagram of such a circuit omitting the details of circuitry which in themselves do not form a part of the present invention and which are within the ability of those skilled in the art in view of such patents as the aforesaid Albrecht patent and illustrating only those elements which facilitate an understanding of the present invention. In FIG. 3, the solenoids for controlling the first printing unit have been designated by the reference numerals 36A1, 36A2,

36A3, the solenoid respectively setting the throw mechanism to effect the operation of the plate oif, ink off, and impression olf movements when the solenoids are energized and to effect the respective on movements when the solenoids are de-energized. The solenoids for the second unit have been designated in a similar manner with the letter B being substituted for the letter A; in the third unit the letter C has been substituted for the letter A, etc. The trip control circuits for each printing unit are represented by the block 40A, 40B and 40C. The trip control circuits 40A, 40B and 40C may essentially comprise known circuits.

The trip control circuit 40A for the first printing unit includes relays 41A1, 41A2, 41A3 which are energized to effect an energization of the solenoid 36A1, 36A2, 36A3 for respectively controlling the plate on, ink on motions. and impression on movements. The relay 41A3 for controlling the energziation of the solenoid 36A3 is energized in a known manner in each revolution of the impression cylinder to prevent the impression on movement from occurring unless the preceding unit has thrown on.

Similarly, relays 41B1 and 41B2, 41B3, 41C1, 41C2. 41C3, etc. are provided for controlling the trip solenoids of the other units. The control of the trip circuits for effecting the throwing on and olf in sequence of the printing units may be by a trip controller 43 as described in Albrecht Patent No. 2,615,393 which includes switch means which is operated during each revolution of the press in response to the absence of a sheet to keep the press tripped off.

In the Albrecht patent all the inkers and plates of the press may be thrown on by the trip controller when a sheet approaches the first printing unit but the impressions are not thrown on until a sheet reaches the particular printing unit. Consequently, the controller circuit is such that the energization of the relays for controlling the plates and inkers can be prevented while maintaining the impression relays energized as necessary to keep the impressions 01f.

Alternatively, the relays for controlling the various plate on, ink on, and impression movements may be controlled by gripper fingers immediately ahead of each unit as in Harrold et al. Patent No. 2,578,700.

When no sheets are proceeding through the press, all the relays will be energized, at least during the respective control portion of the cycle, to energize the solenoids for controlling the trip means to maintain the printing units oif pressure. If any one of the relays are de-energized, the trip movement controlled thereby will occur the next time that the throw member for the trip mechanism moves through its operating stroke.

In the control illustrated in FIG. 3 the plate on and off movement controls the energization of the ink relay 41A2. The ink relay 41A2 is energized through a circuit including a switch 49A which is opened when the plate mechanism is actuated to throw on the plate. The opening of switch 49A breaks the energizing circuit for the relay 41A2 and in turn the solenoid 36A2. Similarly when the plate mechanism is actuated to throw off the plate, the switch 49A is closed to energize the relay 41A2 so that the inker will be tripped off in sequence. The inker relays in the other units are similarly controlled.

In accordance with the present invention, circuit means is provided for breaking the circuits for energizing the solenoids for controlling the plates and inkers for a predetermined number of press revolutions and then to again make the circuits so that the cams will effect the throw off of the printing unit and continue under the operation of the control means to maintain the units in an off condition unless a sheet is proceeding through the press.

The circuit for energizing the solenoids 36A1 includes normally closed contacts BR-l of a relay BR. When the relay BR is energized to open its contacts BR-l, the relay 41A1 is not energized at the time of the work stroke of the throw mechanism of the respective trip mechanism and the trip mechanism will operate to throw on the plate of the first unit. The inkers are thrown on after the plates by the opening of the switch 49A which is operated to an open condition by the actuation of the mechanism to throw on the plate.

The relay BR also has normally closed contacts BR-Z, BR-3 in the circuits for energizing the solenoids 36B1, 36C1, etc. so that the circuits for these relays are broken at the same time as the circuit for the solenoid 36A1, and the plates immediately thrown on within 360 of press rotation. The ink relays corresponding to the ink relay 41A1 are controlled like the ink relay 41A1 and the inkers therefore are thrown on in response to the plate on movement.

The relay BR may be energized by the operator of the press to effect a throwing on of the plates and inkers only to prepare the printing press for operation. The press controls include a switch 50 which may be operated from an ofi condition to an on condition to energize the relay BR. When the switch 50 is moved to its on position, a switch arm 53 engages an ON contact 52 to apply a potential to the contact. The contact 52 is connected to the input of a monostable multivibrator 54 for passing a pulse to trigger the latter to its unstable state to provide an output pulse for switching a bistable memory circuit or flip flop 56. The flip flop 56 has circuit portions 56A and 56B which are either in a conductive or non-conductive condition. When one of the circuit portions 56A, 56B is conductive, the other is non-conductive and the state of the circuit can be switched by applying a pulse signal thereto. When a pulse signal is applied through the gate 54 to the circuit portion 56A the circuit is set to condition an AND gate 55 to pass a pulse signal to a bistable multivibrator circuit 57 to turn the circuit on to energize the relay BR and when a signal is applied to circuit portion 56B, the circuit 56 switches to a condition removing the input to gate 57.

The pulse signal which effects the triggering of the bistable circuit 57 to its condition where the relay BR is energized is provided by a pulse generator 58 including a member which rotates in timed relation to the press and applies a pulse to the gate 55 at the end of each cycle so that the relay BR can be energized only immediately at the start of a press cycle. The pulse generator 53 may comprise a wheel with a slot therein which passes light to a photocell or a magnetic member 59 which is rotated past a pick-up coil 60 to provide an output signal immediately before the beginning of each cycle to the gate 55.

Preferably, the pick-up 60 is located in advance of the zero degree position and a zero degree pulse is de rived from a second pickup head 62 located at the press zero position of the pulse generator. The pick-up head 62 counts press revolutions and once at the beginning of each cycle a pulse is applied to an AND gate 64 which has its output connected to the input of a counter 66. The operation of the switch 50 to its on position conditions the gate 64 to pass the pulses from the nick-up head 62 to the counter 66 so that the counter 66 counts revolutions of the press. In the illustrated embodiment, the counter has five outputs and a signal appears on output 66:: after one revolution, on 66b after two revolutions, on 660 after three revolutions, on 66d after four revolutions and on 662 after five revolutions. A switch 68 may be operated to select any of the outputs and to connect the output through a difierentiating circuit 67 to the off side 56b of the bistable circuits 56, 57. When a signal appears on the output of the counter selected by the switch 68, the bistable circuit 57 will be switched to its condition for de-energizing the relay BR and to open its relay contacts. The opening of the relay contacts BR-l will return the solenoids 36A1, 36A2, 36B1, 36132, etc. to the control of the trip controller.

The relay BR also has normally closed contacts BR- connected to the on contact 52 of the switch 50. When the relay BR is de-energized and switch 50 is in its on position, the contacts BR-10 are closed to apply a potential to all of the plates on relays 41A1, 41B1, etc. This will assure that all of the solenoids are energized within 360 of press revolutions to efiect a tripping off of the printing press. When all plates and inkers are ofi the BR4 switch, 50 is moved to its off position which resets the counter through a connection 68, including a difierentiating circuit 69.

In certain presses, it may be convenient to eliminate the separate relay 41A2 and control the ink trip solenoid with the relay 41A1 or mechanically from the plate trip mechanism.

FIG. 4 illustrates another form of control circuit for the type of trip means in which the solenoid is energized to efiect a tripping off of the motion controlled thereby. The solenoids for each trip movement 36A1, 36A2, 36A3, 36131, 36B2, 36B3, which are illustrated as being ener gized by circuits which include normally closed contacts of relays 41A1, 41A2, '41A3, 41B1, 41B2, 41B3. Each of these relays is controlled by a corresponding bistable circuit 70A1, 70A2, 70A3, 70B1, 70B2, 70B3. Normally the circuits are in a condition where the control relays 41A1, 41A2 are de-energized. When it is desired to throw on the printing press a switch 72 is closed to energize an on relay 73 having normally open contacts 73-1 and self-holding contacts 73-2. When the contacts 73-1 are closed, an ON gate 75A is conditioned to pass a press zero signal to the bistable circuit 70A1 to change the state of the circuit to energize the relay 41A1.

The press zero signal is derived from any circuit means and is shown schematically as a switch 77 which is closed momentarily as the press moves through press zero for each 360 rotation of the printing couples. The closing of the switch 77 applies a signal to an input 75A1 of the gate circuit 75A to change the state of the bistable circuit 70A1 to energize the relay 41A1 which in turn de-energizes the solenoid 36A1 to allow the trip mechanism to throw on the plate of the first printing unit. The turning on of the circuit 70A1 provides an input to a one shot multivibrator 78A to trigger it to its unstable state to supply a pulse signal to turn on the inker and impression bistable circuits 70A2, 70A3. The switching on of the bistable circuit 70A2 effects an energization of the relay 41A2 to open the circuit for energizing solenoid 36A2 so that the inker will also be thrown on. The signal from the monostable multivibrator 78A is applied to the impression bistable circuit 70A3 through an AND gate 82A for operating the bistable circuit 7 0A3 to its on condition to effect a throw on of the impression unit. During normal printing press operation, the gate 82A is conditioned to pass the signal from the multivibrator 78A and will effect an energization of the relay 41A3 to deenergize the solenoid 36A3 to effect a throwing on of the impression motion in proper sequence to the throwing on of the plate and inkers. When the impression of the first unit is thrown on, a switch 84 is operated to close its contacts 84a to apply a signal to an on AND gate 75B for the second printing unit. The signal from the switch 84 conditions the gate 75B to pass a zero signal from the switch 77 to trigger the bistable circuit 70B1 to its condition for energizing the relay 41B]. to de-energize the solenoid 36B1. The operation of the plate bistable circuit 70B1 of the printing unit B provides a signal for the ink on bistable circuit 70B2 which in turn applies a signal to the impression on bistable circuit 70B3 through an AND gate 82B in the same manner as in the control means for the first printing unit and this description will not be repeated. Similarly, the circuit for controlling the unit C and following units are duplicates of the preceding units and these controls have not been shown and the description thereof will not be repeated.

To throw off the units, a switch is momentarily closed to energize an off relay 92. The otf relay 92 has normally closed contacts 92-1 in the holding circuit for the on relay 73 and contacts 92-2 which are closed to supply an off signal to an off AND gate 94A of the first printing unit. The off gate 94A has an output connected to the bistable circuit 70A1 for the printing unit A and when conditioned by the off signal will pass the press zero signal 77 to trigger the bistable circuit 70A1 to its state where the relay 41A1 is de-energized. The de-energization of the relay 41A1 will cause the plate to trip off at the proper time of the cycle as determined by the cam of the trip mechanism. The turning off of the plate bistable circuit 70A1 provides an input to a monostable multivibrator 95 to switch it to its unstable state to provide a pulse signal to turn off the ink bistable circuit 70A2 to effect a de-energization of the relay 41A2 and to the bistable circuit 70A3 to effect operation of the bistable circuit 70A3 to effect a de-energization of the relay 41A3 to effect a tripping off of the impression. The operation of the impression control means to a trip off condition effects operation of the switch 84 to close its contacts 84b to apply a signal to an OFF gate 943 of the second printing unit. When the off AND gate 94B is conditioned by the switch 84, it will pass the zero signal from the switch 77 to the off bistable circuit of the second printing unit to cause the plate of the second printing unit to trip off in that portion of the cycle as determined by the cam of the trip mechanism. In the same manner as in the first printing unit, the switching of bistable circuit 70B1 will operate to effect a throw off of the inker and impression in sequence.

The control circuit illustrated in FIG. 4 also includes controls for throwing on all of the plates within 360 of press revolution and the inkers in sequence.

In FIG. 4 a switch 100 may be moved to an on position to supply a potential through a differentiating circuit 101 for operating a bistable memory circuit 102 to an on condition for supplying gate conditioning signals to AND gate 103 and a gate 104. The output of the gate 103 is connected to a plurality of AND gates 106A, 1063, etc., one for each printing unit. The gates 106A, 1063 when conditioned by the signal from the gate 103 are conditioned to pass the press zero from the switch 77 to turn on the plate on bistable circuits 70A1, 70B1, etc. and to operate the trip mechanism in the same manner as when the signal is passed by the on gates 75A, 75B. However, since all of the gates 106A, 106B are conditioned at the same time, all units will be conditioned by the same press zero signal to be thrown on starting in the same press revolution. If no further control were provided, the impression cylinders would also be thrown on. In accordance with the present invention, the impression control gates 82A, 82B are connected to an output 107 of the bistable circuit 102 and when the bistable circuit 102 is in its condition to condition the gate 103, there is no signal on the output 107 and the gates 82A, 82B are closed and will not pass a signal to effect a switching of the bistable circuits 70A3, 70B3, etc. to effect a throwing on of the impression cylinders. Therefore, only the bistable circuits 70A1, 70A2, 70B1, 770B2, etc. will be operated in response to the operation of switch 100 to throw on the plate and inking units.

The gate 103 will not provide a throw on conditioning signal to the gates 106A, 106B until a bistable circuit 110 is switched to a gate conditioning condition. This is done in response to a signal derived immediately in advance of the press zero signal, the signal for switching the bistable circuit 110 may be derived in any manner and is schematically shown as derived by momentarily closing a switch 112. The closing of the switch 112 applies a signal to the AND gate 104 which is conditioned to pass the signal by the switching of the bistable circuit 102 to its condition for conditioning the gate 103. The output of the AND gate 104 effects the switching of the bistable circuit 110 to its on condition to apply a gate conditioning signal from the bistable circuit 110 to the AND gate 103. The output of the AND gate 104 is also applied to a counter 114. The counter 114 counts the number of press revolutions by counting the signals from the switch 112 and has a plurality of outputs connected to a switch 116 which may be set to select the output and the number of revolutions which are to occur before all of the printing units are to be returned to an off condition. When this number of press revolutions occurs, a signal is derived from the switch 116 which is applied to the bistable circuit 102 to switch the latter to an off condition to remove the gate conditioning signal from the gate 103 and to apply a signal over output 107 to a gate 118 whose output is applied to condition off gates 120A, 120B, etc. to pass a press zero signal to the bistable circuits 70A1, 70B1 to switch the circuits to their orf condition to effect a trip off of the units. The gate 118 has one input connected to the switch to condition the gate to pass the off signal from the bistable circuit 102. Consequently, when the switch 100 is moved to its off position, the gate 118 nolonger functions to condition the gates A, 120B, etc. to trip off the printing units in response to a zero signal.

The return of the bistable circuit 102 to its off condition in response to the signal from the counter again conditions the gates 82A, 82B to pass the signals for tripping the impression cylinders on upon the operation of inker throw on mechanism.

If the printing units are out of phase as in the illustrated machine, certain of the units may have a plate on movement in one revolution as measured by the press zero signal and an ink on motion in the next revolution. While the press zero signal does not occur at the time that the units are to be operated, the interlocking of the units through the switches 78, 84 assures that the tripping on of the plate will occur first and the inkers and impressions will be tripped on in sequence thereafter.

The control signal for setting the inker and impression cylinder circuits to throw on condition and the signal for conditioning the following unit may be derived from the plate on control circuitry itself and be applied with a delay as by use of a monostable multivibrator circuit. to the subsequent circuits to assure that the press zero switch has opened.

The on switch 72 may be operated from the feeder for the press so that it is momentarily closed when the feeding of sheets is started. It will be noted that the off relay 92 has a self-holding circuit including its normally open contacts 92-3 and normally closed contacts 733 of the on relay 73 so that if the on relay is energized the otf relay will drop out.

The printing press may also include a control each for effecting only the plate on or inker on movements. A plate on switch may be provided and when operated to its on condition, may energize a relay 131 having normally open contacts 1311 which are closed to energize the plate control relays 41A1, 41A2, etc.

The operation of relay 41A1 will not effect a tripping on of the inker and impression since the bistable circuits 70A1, 70B1, etc. remain in their off condition and no signal occurs to trigger the inkers in response to the throwing on of the plate.

Similarly, an ink on switch 132 may energize an ink on relay 133 to close its contacts 133-1 to energize the relays 41A2, 41B2, etc. The impressions will not throw on when the inker relay is energized since the circuits 70A2, 70B2, etc. remain off.

No mechanism has been shown to operate the press zero switches 77 and 112. They may be operated by a cam rotated with the press or a pulse generator, as in FIG. 3, may be substituted.

While the present invention has been described in a type of printing press where a solenoid is energized to maintain the throw mechanism for a particular unit in an off condition, it will be appreciated that the relays 41A1, 41A2, 41A3 and the corresponding relays in the other printing units may be energized to effect the energization of the solenoid to set the throw mechanism to throw on and de-energized to eflect the de-energization of that solenoid and the energization of another solenoid to set the throw mechanism to throw 01?.

What is claimed is:

1. In an ofiset printing press, a plurality of printing units each comprising: a plate cylinder, a blanket cylinder and an impression cylinder, and an inker for inking said plate cylinder, first means for tripping said inker on and off and for tripping said plate and blanket cylinders on and off pressure, second means for tripping said blanket and impression cylinders on and off pressure to print an impression, and first and second control means for each of said first and second means for operating the latter to efiect the respective throw on and throw ofi movements; means for effecting operation of said first and second control means of each unit to sequentially throw said printing units on and oif in sequence as a sheet moves through the press and additional means for effecting operation of said first control means in all of said units within 360 of press rotation to initiate the throw on of the inker and said plate and blanket cylinders only of said units and to subsequently initiate the throw oil of said inker and said plate and blanket cylinders of all of said units within 360 of press rotation after a predetermined number of press revolutions.

2. A multi-color printing press as defined in claim 1 in which said additional means includes means actuatable to throw on said inkers and said plate and blanket pressures and for preventing the tripping on of said impression cylinders in response to said timing signals.

3. A printing press as defined in claim 1 wherein said first means of each unit comprises separate first and second mechanisms for independently tripping the inker on and OE and for tripping the plate and blanket cylinders on and oil" pressure and each of said units comprises control means for selectively actuating said first and second mechanisms independently of each other and of said second means.

4. A printing press as defined in claim 1 wherein said additional means comprises control means actuatable to eflFect the trip on of only said inkers and of said plate and blanket pressures in response to said timing signals, counting means responsive to said control means for counting press revolutions and means responsive to said counting means for tripping oflf said inkers and said plate and blanket cylinders after a predetermined number of revolutions.

5. A printing press having a plurality of printing units to be rendered operable to print a sheet in sequence as a sheet arrives at the units as it proceeds through the press, electroresponsive means for operating each unit between printing and non-printing conditions, signal producing means providing repetitive timing signals in sequence, pulse responsive mean including pulse responsive circuit means for each unit for gating said timing signals to effect the operation of said electroresponsive means of the unit and including means for sequentially supplying electrical signals to sequentially condition said pulse responsive circuit means to be responsive to said signal producing means in sequence to render said units operable to print a sheet as it moves through the press.

6. A printing press as defined in claim 5 wherein each of said electroresponsive means includes a first electrically controlled means operable irom an oil to an on condition for effecting an inking of the printing cylinder and a second electrically controlled means operated for effecting the throwing of the printing pressure of the unit on and OE and in which said printing press includes additional control means for setting the first electrically controlled means of said units to etfect the inking of the printing cylinder in response to said timing signals without sequencing the operation of the units and to prevent the operation of the second electrically controlled means of said units and to return said first electrically controlled means of said units to their oif conditions without sequencing the units after a predetermined number of press revolutions.

7. A printing press as defined in claim 6 wherein said additional control means includes a counter for counting press revolutions and settable to select the number of press revolutions which are to occur before said first electrically controlled means of said units are returned to their oif condition and means responsive to said counter to set said first electrically controlled means of said units in their 01f conditions.

References Cited UNITED STATES PATENTS 2,003,800 6/1935 Barber 101-177 2,615,393 10/1952 Albrecht 101--184 3,195,456 7/1965 Charlwood et al. 10l184 3,259,060 7/ 1966 Martin 101247 XR ROBERT E. PULFREY, Primary Examiner I. REED FISHER, Assistant Examiner U.S. Cl. X.R. 

